A first group of such apparatuses uses a particle accelerator and deflects a part of the beam on to the electronic circuit. However, the use of such apparatuses is complicated and heavy, so that irradiators have been constructed which are particularly adapted to this use. They mainly comprise an evacuated enclosure in which the circuit to be tested is placed, a dosimeter to characterize the radiation, and a radioactive source. One of them forms the subject matter of U.S. Pat. No. 4,575,676 in the name of Palkuti. The radiation source is a X-ray tube and logical safety devices are also provided which interrupt the emission of X-rays if a shutter and the evacuated enclosure are opened simultaneously. The irradiator requires the use of a microcomputer for this purpose. It also has the disadvantage of not ensuring circuit-radiation conditions which are equal to those measured by the dosimeter, since it mentions no means of positioning or precise control.